Methanol colority

National Standard of the People’s Republic of China: Methanol for industrial use GB 338—92, replacing GB 338—85. Industrial Methanol 1. Subject matter and scope: This standard specifies the technical requirements, testing methods, inspection rules, as well as requirements regarding labeling, packaging, transportation, and storage of industrial methanol. This standard applies to industrial methanol synthesized from raw materials such as coal, coke, natural gas, light oil, and heavy oil. Molecular formula: CH3OH; Relative molecular mass: 32.042 (based on the international relative atomic masses of 1989). 2 References: GB 190 – Marking for packaging of dangerous goods; GB 601 – Preparation of standard solutions for titrimetric analysis (volumetric analysis) in chemical reagents; GB 1250 – Methods for expressing and determining limit values; GB 3143 – Method for determining the color of liquid chemical products (Hazen unit – platinum-cobalt color scale); GB 4472 – General rules for determining the density and specific gravity of chemical products; GB 6283 – Determination of moisture content in chemical products – Karl Fischer method (general method); CB 6324.1 – Test methods for water solubility of organic chemical products; GB 6324.2 – Volatile organic liquids – General method for determining the dry residue after evaporation in a water bath; GB 6678 – General principles for sampling chemical products; GB 6680 – General principles for sampling liquid chemical products; GB 7534 – Determination of the boiling range of industrial volatile organic liquids; GB 8170 – Rules for rounding numerical values. 3 Technical requirements: 3.1 Industrial methanol should be a colorless and transparent liquid without any special odor or visible impurities. 3.2 Industrial methanol shall meet the requirements specified in Table 1: Table 1 | Item | Specification | Top Grade | First Grade | Qualified Grade | Colority (platinum-cobalt), number ≤ 5 10 | Density (20°C), g/cm3 0.791–0.792 0.791–0.793 | Temperature range (0°C, 101325 Pa), °C | Boiling range (including 64.6±0.1°C), °C ≤ 64.0–65.5 0.8 1.0 1.5 | Potassium permanganate test, min ≥ 50 30 20 | Water solubility test: Clear | Moisture content, % ≤ 0.01 0.15 – | Acidity (as HCOOH), % ≤ 0.001 5 0.003 0 0.005 0 or Alkalinity (as NH3), % ≤ 0.000 2 0.000 8 0.0001 5 | Aldehyde compound content (as CH2O), % ≤ 0.002 0.005 0.010 | Evaporation residue content, % ≤ 0.001 0.003 0.005 4 | Test methods: The reagents and water used in these test methods are, unless otherwise specified, of analytical grade and distilled water or water of equivalent purity. 4.1 Determination of chroma: The determination is carried out in accordance with the provisions of GB 3143. 4.2 Determination of density 4.2.1 Pycnometer method 4.2.1.1 The determination is carried out at room temperature in accordance with the provisions of 2.3.3 in GB 4472. The indication range of the densitometer is 0.750～0.800 g/cm3. Within the temperature range of 15–35°C, the temperature correction coefficient K for the sample density is 0.000 93 g/cm3°C. The result is the arithmetic mean of two parallel measurements. 4.2.1.2 Allowable difference: The difference between the results of two parallel measurements shall not be greater than 0.0005 g/cm3. 4.2.2 Pycnometer method (arbitration method) 4.2.2.1 The determination is carried out in accordance with the provisions of 2.3.1 in GB 4472. The result is the arithmetic mean of two parallel measurements. 4.2.2.2 Allowable difference: The difference between the results of two parallel measurements shall not be greater than 0.0005 g/cm3. 4.3 Determination of boiling range: It shall be determined in accordance with the provisions of GB 7534. The range of the main thermometer’s reading is 50–70°C, and the specifications of the condenser meet the requirements of 3.4.1 in GB 7534. The correction value for boiling point temperature due to changes in air pressure shall comply with the provisions in Table 2. Table 2 Air pressure, kPa: 773–813, 814–866, 867–933, 934–986, 987–1,066. R value, °C/Pa: 2.78×10^-4, 2.70×10^-4, 2.62×10^-4, 2.55×10^-4, 2.48×10^-4. The values below the standard range are not listed.

1. Program for the methanol viscosity curve: *=; cpi=; x=-10:70; P=polyfit(*,cpi,3); cp=polyval(P,x); plot(x,cp).
2. Conversion between concentration units ppm and mg/m3: Use the following formula: mg/m3 = M/22.4•ppm•*(Ba/101325). In this formula: M represents the molecular weight of the gas; ppm represents the measured volume concentration; T represents temperature; Ba represents pressure.

Internal link: GB 3143 – Method for determining the color of liquid chemical products (Hazen unit – Platinum-Cobalt scale): http://bbs.hcbbs.com/viewthread.php?tid=155080&highlight=GB%2B3143. This post was last edited by lifanwang on 2009-3-21 at 12:29